Cholesterol mediates spontaneous insertion of Lycium barbarum polysaccharides in biomembrane model
Autor: | Ziyi Zhang, Runguang Sun, Xianggang Zhang, Hengyu Liu, Changchun Hao |
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Rok vydání: | 2019 |
Předmět: |
Langmuir
Hydrogen bond General Chemical Engineering 02 engineering and technology Surfaces and Interfaces General Chemistry Entropy of mixing 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Crystallography symbols.namesake Gibbs isotherm chemistry Monolayer symbols Molecule van der Waals force 0210 nano-technology POPC |
Zdroj: | Adsorption. 26:855-862 |
ISSN: | 1572-8757 0929-5607 |
Popis: | In this work, the adsorptive behavior of Lycium barabrum polysaccharides (LBP) on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and POPC/DPPC/Cholesterol (Chol) monolayer films were investigated using the Langmuir films technique and atomic force microscopy (AFM). For the POPC/DPPC system, the π-A isotherms shifted to larger areas and the surface pressure variations (Δπ) in the adsorption curves (10 mN/m and 35 mN/m) increased with the increase in the LBP concentration. For the POPC/DPPC/Chol system, π-A isotherms moved to larger areas with the addition of LBP, and the Δπ values were also lower than those of the POPC/DPPC system. These were ascribed to hydrogen bond network formation between LBP and the lipids. The excess per molecular area (ΔAexc) and the excess Gibbs free energy of mixing ( $$\Delta {\text{G}}_{mix}^{Exc}$$ ) revealed that the repulsion force was the interaction between POPC and DPPC molecules. Meanwhile, the repulsion force increased with the addition of LBP. The addition of cholesterol decreased the force. The interactions among molecules were also evaluated by the values of K (the speed of adsorption of LBP), Ap (the number of each lipid molecule combining with the polysaccharide molecules in the mixed monolayer), Γ (the surface excess concentration) and A (the area per molecule). As shown in AFM images, the morphology of the monolayer films also indicated that LBP was easily adsorbed onto the POPC/DPPC monolayer film via hydrogen bond and the weak Van der Waals interaction. In summary, cholesterol could affect spontaneous insertion of LBP into the POPC/DPPC monolayer films from phosphate buffer solution. |
Databáze: | OpenAIRE |
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